Reversible water-cooled open hearth furnace doors



March 19, 1963 R. J. DEMAISON 3,081,751

REVERSIBLE WATER--COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11. 1959 ssheets-snei 1 INVENTOR E J flz-"mw/so/v BY m4. 2 6/ March 19, 1963' R.J. DEMAISON Y 3,081,751

REVERSIBLE WATER-COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11, 1959 3She ets-Sheet 2 ATTO N March 19; 1963 R J DEMAISON REVERSIBLEWATER-COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11, 1959 3Sheets-Sheet 3 THZ EI.

INVENTOR A. J DEMA/SO/v M M %ZI% 3,081,751 REVERSKBLE WATEit-(IOOLEDOPEN HEARTH FURNAOE DOORS Raymond J. Dernaison, Bronx, N.Y., assignor toQuigiey Company, inc, a corporation of New York Filed Aug. 11, 1959,Ser. No. 832,954 3 Claims. (Cl. 122-498) This invention relates tofurnace doors for use on open hearth furnaces and in particular relatesto the type of door which is water cooled and contains a refractorymaterial insert or lining.

The principal feature of this invention is to provide a water cooledreversible furnace door having suitable refractory inserts or linings onboth faces and capable of being reversed as desired to allow one face orthe other to be brought into service without removing the door from thefurnace.

Other features of the invention are to provide a reversible Water-cooledfurnace door that is economical to repair due to the novel methodemployed in placing the refractory material in the furnace door andwhich in addition is long lived due to the increased heat transfereffected by the reinforcing, attaching and supporting means employed inplacing the refractory material in the faces of the door. The necessityof removing the door from the furnace for repairs is entirelyeliminated.

The present invention therefore contemplates certain improvements in theconstruction of the furnace door which definitely overcome one of thegreatest difliculties encountered in the operation of an open hearthfurnace. The common method of removing the single refractory faced doorsperiodically for repair is one which is very costly and time consumingand in addition requires a very large space just to effect the repairs.

The present invention may be briefly described as directed to an openhearth furnace door comprising a watercooled supporting frame faced onboth sides with refractory material and reversible to bring eitherrefractory facing into service. On the faces of the water-cooledsupporting frame are placed a plurality of anchoring and reinforcingmeans for the insertion of suitable refractory material and saidanchoring means, in addition to holding the refractory material inplace, assists and controls the transfer of heat from the refractorymaterial inserts to the supporting frame. The normal water cooling inletand outlet pipes are employed to supply water to the door for coolingand will be disconnected at the unions when the door is to be reversed.

The furnace door is provided with a tilting pad and trunnion in thecenter of its lower edge to which a crank hook may be attached and thedoor lifted to a horizontal position. At its top edge, the furnace dooris pivoted to permit such upward tilting and moreover is provided with atrunnion in axial alignment with the lower trunnion. Hence, when thedoor is in its horizontal position, it may be reversed by rotating itthrough 180 about a centrally located axis and thereafter lowered backto its normal vertical operative position. In this way, a new refractoryfacing is located on the furnace engaging side of the door while thedamaged facing is located on the outside and may be repaired in placewithout any trouble whatsoever with the furnace in operation. Thewater-cooled supporting frame keeps the damaged face cool.

In the normal operation of the furnace, the door may be raised orlowered (in its own plane) in the usual way by means of one or twolifting chains. Where one chain is employed, the top trunnion is builtright into the lifting eye.

Referring to the drawings:

FIG. 1 is a front elevation of an open hearth furnace door constructedin accordance with the invention;

FIG. 2 is a vertical section taken along the lines 2-2 of FIG. 1;

FIG. 3 is a front elevation of a modified form of fur nace door alsoconstructed in accordance with the invention;

FIG. 4 is a vertical section taken along the lines 4-4 of FIG. 3;

FIG. 5 is a front View of one of the refractory blocks shown in FIG. 3;

FIG. 6 is an edge view of the refractory block shown in FIG. 5;

FIG. 7 is an enlarged sectional view of the refractory block shown inFIGS. 5 and 6; and

FIG. 8 is a detailed perspective view of the reinforcing grid embeddedin the individual refractory blocks.

The improved furnace door comprises a rectangular symmetrical metalsupporting frame it presenting a wide hollow rim portion 1i and arelatively narrow centrally located hollow body portion 12, the framethus having passages for the circulation of water or other cooling fluidtherethrough and serving as a cooling jacket for the refractorymaterial. Water pipes 13 and 14 are tapped into the top rim portion ofthe frame adjacent its opposite ends and are detachably connected bycouplings 15 and to to flexible inlet and outlet tubes 17' and 18,respectively. In one position of the door, the pipe 13 will be connectedto the inlet tube 17 and the pipe 14 to the outlet tube 18, while in thereversed position of the door, the pipe .14 will be connected to theinlet tube 17 and the pipe 13 to the outlet tube '18.

A cylindrical sleeve or thimble 19 passes through the body portion 12from one side of the door to the other and forms the customary wicketopening or peep hole for furnace observation.

in FIGS. 1 and 2, the furnace door is faced on both sides of the bodyportion 12 with refractory material in the form of monolithic slabs Z0and 21. To insure the retention in place of the slabs, the inner walls22 of the rim portion 11 are inclined with reference to the central bodyportion 12 in order to overhang the slabs around their perimeters. Onits opposite sides, the body portion 12 has welded thereto a multitudeof metal pins 23 which not only serve to reinforce the monolithic slabsand anchor them in place but in addition to serve as heat exchangeelements to conduct heat from the slabs to the water-cooled supportingframe.

The monolithic slabs may be built into the supporting frame by casting,trowelling, spraying or in any other desired manner. After a certainperiod of time, the slabs will of course deteriorate under the influenceof the furnace heat and will need to be repaired or replaced. Completereplacement will seldom be necessary, since the slabs may be readilyrepaired by patching or spraying. As before stated, when the slab inservice becomes damaged, the door is reversed to bring the other slabinto service, and then the damaged slab may be repaired from the outsidewhile the door is in place and the furnace in operation.

In FIG. 2, the door is shown in its normal vertical operative position,being located on the outside of the furnace wall A and closing the dooropening B therein. In the normal operation of the furnace, the door willbe raised and lowered in its own plane to open and closed positions,respectively. This is done by means of a pair of lifting chains 24attached to the top of the supporting frame through the medium of alifter bar 25. The bar 25 is provided on its opposite ends withbifurcated brackets 26 having cross pins 27 which pass through eyes 28of the lifting chains. The pins 27 and eyes 28 thus form a pivot aboutwhich the door may be swung upwardly (away from the furnace wall A) to ahorizontal position for reversal and thereafter swung downwardly forreturn to its door closing position.

Below the lifter bar 25 and extending parallel thereto is a hanger bar29 which is swivelled thereto by means of a trunnion bearing bolt 3%passing through openings in the two bars and having suitable washerswhich permit the hanger bar to be rotated freely with respect to thelifter bar. The hanger bar 29 could be rigidly attached to the top ofthe supporting frame (as in the second embodiment later described) butit is preferred, in tihs instance, to provide for a limited rockingmotion between the bar and the supporting frame in order to allow thelatter some freedom of movement as it is raised and lowered by thelifting chains 24 and also during its upward and downward swingingmovements. Accordingly, the hanger bar 29, near its opposite ends, isformed with depending rectangular plates 29a connected by hinge pins 31to bifurcated brackets a welded to the top of the supporting frame 10.As indicated by the dotted lines in FIG. 2, the lower edges of theplates 29a extend parallel to and closely adjacent the flat bases of thebrackets 16a, permitting the desired amount of relative movement betweenthe supporting frame and the hanger bar 29.

' It will now be seen that, when the door is swung upwardly to ahorizontal position, it is free to be rotated through 180 for reversal,the axis of rotation passing centrally through the door which thusoccupies the same relation to the other parts when either refractoryfacing is in use.

As a convenient and practical way of effecting the pivotal or swingingmovements of the door, the supporting frame 10 is provided at its loweredge with a tilting pad 32 which is swivelled thereto by means of athreaded trunnion bearing stud or pin 33 arranged in axial alignmentwith the top trunnion bearing bolt 30. The free end of the tilting padis formed with an eye 34 to receive the hook 35 of a lifting crane. Aswill be evident, the pad will not only serve as a connection between thelifting crane and the door but will also act to support the door in itshorizontal position, its swivel connection with the door permitting itto be rotated through 180 for reversal in the manner above described.

It may be noted that, in this particular embodiment, a recess (notshown) will be formed in the sill or platform of the furnace toaccommodate the lifting pad 32 and trunnion stud 33. This is because thedoor normally rests at its lower edge upon the furnace hearth forsupport and proper location. The limited relative rocking movementprovided between the door and the hanger bar 29 facilitates theattachment of the crane hook 35 to the tilting pad 32.

Referring now to the second embodiment shown in FIGS. 3 to 8:

In this embodiment, the water-cooled supporting frame lfia issubstantially the same as the frame 10 in the first embodimentdescribed, comprising a hollow rim portion 11a and a central hollow bodyportion 12a. In this econd embodiment, however, the inner walls 22a ofthe rim portion are not inclined with respect to the body portion 12abut extend at right angles thereto so as to present rectangular spacesat opposite sides of the frame for the refractory material. In thissecond embodiment, also, the supporting frame is formed with a recess 36to accommodate the lifting pad 32 and trunnion stud 33, thus avoidingthe necessity of cutting a recess in the furnace sill or platform. Thesame wicket opening thimble 19 passes through the supporting frame forobservation urposes, but in this disclosure is kept short in order toprevent burnoff.

As a characteristic feature of the second embodiment under discussion,the refractory facings on opposite sides of the supporting frame are inthe form of separate blocks of panels individually attached to andsupported on the supporting frame. One of the blocks, designated 40, is

shown in FIGS. 5 and 6. It is rectangular in shape and has embeddedtherein a metal grid consisting of two metal strips 41 and 42 arrangedat right angles to each other and welded together in the zone ofintersection. The opposite ends of each strip are bent outwardly fromthe plane of intersection to provide offsets 43 which extend in thedirection of thickness of the blocks. The offsets 43 are split centrallyand then bent in reverse directions to provide tabs 44- which extendparallel to the face of the block. The metal grid therefore not onlyaffords a good reinforcement for the refractory block but also acts asan effective heat exchange element therefor.

As will be observed in FIGS. 6 and 7, the metal strips 41 and 4.2 intheir plane of intersection are located substantially flush with theinner or cool face of the block and are formed with a central opening 45to permit the block to be attached to the supporting frame. Suchattachment is effected by a threaded stud 46 welded to the face of thecentral body portion 12a of the supporting frame and passing through theopening 45. A nut 47 is screwed onto the threaded stud clamps the blockin place. In this connection, it is pointed out that the block, duringcasting, is cored out to leave a hole 45 through the block to giveaccess to the fastening means when the block is attached to thesupporting frame. After attachment of the block, the hole 45 is filledwith the same refractory material as the block is made of to protect thefastening means from the heat of the furnace.

FIGS. 3 and 4 show the furnace door as faced on both sides with theblocks 40, it again being noted that the blocks are individuallyattached to and supported by the metal supporting frame. While notnecessary, it is desirable before mounting the blocks in place, to coatthe faces of the supporting frame with high temperature cement inplastic condition in order to force the cement between the blocks andthus seal the joints between them, see in particular FIG. 7. Tofacilitate the flow of the cement into the joints, the blocks arebevelled or chambered at 48 on their inner or cool faces (see again FIG.7 as well as FIG. 6). Nevertheless, after all the blocks have beenanchored in place, the cement between the joints on the outer or heatexposed faces of the blocks is cut back a suitable distance in order toallow for expansion and contraction of the faces of the refractoryblocks when the furnace is in operation.

The use of separate blocks or panels as refractory facings for thefurnace door is particularly advantageous, because the blocks may bepreformed and then readily mounted in place. Moreover, it ofen occursthat the refractory facings will become damaged in spots or limitedareas and in such cases the damage can be repaired by merely removingthe blocks in those areas and replacing them with new blocks of the samedesign. Of course, in removing any particular block, the refractorymaterial which fills the cored out hole 45 must first be removed butthat is a simple operation.

One further modification remains to be described. As shown in FIGS. 3and 4, a single lifting chain 5% is employed for raising and loweringthe furnace door during the operation of the furnace. Hence, a trunnionbearing bolt 51, which makes a swivel connection with the door through ahanger bar 52 fixed to the door, is provided at its upper end with aneye 53 to receive the looped end 54 of the lifting chain. In thisinstance, therefore, the eye 53 and chain loop 54 form a single pivotalconnection which permits the door to be swung up to its horizontalposition for reversal and then lowered back into place.

Any suitable high temperature refractory material may be used forforming the door facings. For example, the preformed blocks or panels 40may be made of chromemagnesium, and the same material may be used forfilling the cored out holes in the blocks. In the case of the monolithicslabs, shown in FIGS. 1 and 2, Roofchrome, which is essentially a chromeore composition, may be employed and applied by casting, trowelling orspraying or otherwise. This Roofchrome material may also be used formaking repairs, either to the monolithic slabs or to the preformedblocks, being applied readily by spraying in wet slurry form from a highpressure spray gun.

It will now be appreciated by those skilled in the art that the presentinvention represents a great advance in open hearth furnaces. Thefurnace doors have always presented a major repair problem since theycan only be repaired by removing them from the furnace and replacingthem by other doors. With the instant invention, the doors may bereadily repaired without removing them from the furnace and while thefurnace is in operation, thus saving much time and labor in theoperation of the furnace.

The invention has been shown only in preferred form and by way ofexample, and it will be understood that many changes and modificationsmay be made without departing from its spirit. The invention thereforeis not limited to any particular form or embodiment except insofar assuch limitations are specified in the appended claims.

What is claimed is:

1. In combination,

(a) a reversible open hearth door, comprising (b) a metallic supportingframe faced on both sides with similar separate and distinct inserts ofnonmetallic refractory material,

(c) means for supporting said door from the top of said frame and forraising and lowering said door substantially in a plane into open andclosed position, comprising (d) lifting means above said frame,

(e) a pivotal connection at the top of said frame between said frame andsaid lifting means with a horizontal pivotal axis extending along thelength of the door, and

(f) a swivel connection at the top of said frame between said frame andsaid lifting means and located intermediate of the sides of the door,said swivel connection having its axis extending crosswise of said door,substantially in the plane of said door,

(g) said pivotal connection and said swivel connection being connectedin series between said lifting means and the top of said frame, and

(h) means for swinging said door forwardly and upwardly about saidhorizontal axis from said first mentioned plane to a raisedsubstantially horizontal position and then back again and for supportingsaid door in said substantially horizontal position in conjunction withsaid door supporting means, and comprising (i) a lifting member, and

(j) means for forming a swivel connection between said lifting memberand the bottom of said frame 7 intermediate the sides thereof coaxialwith the top swivel connection (k) said swivel connections permittingrotation of said door '1 80 about said crosswise swivel axis, whereby 5said door when in said raised substantially horizontal position can berotated about said crosswise swivel axis through 1 80 While supported bysaid door supporting means (0) and said door swinging and supportingmeans (h) with said crosswise swivel swivel axis substantiallyhorizontal.

2. The combination as described in claim 1, said means (c) forsupporting said door from the top of the frame, comprising (1) a lifterbar located at the top of said frame and extending along said door,

(111) said pivotal connection (e) comprising means at the ends of thelifter bar for pivotally mounting said bar to said lifting means (d),

(It) said top swivel connection comprising a hanger bar underlying thelifter bar and extending therealong,

(o) said hanger bar having means at its ends pivotally mounting saidhanger bar to the frame for limited movement about an axis parallel tosaid horizontal pivotal axis,

(p) said top swivel connection also comprising a trunnioninterconnecting the intermediate section of said hanger bar and theintermediate section of said lifter bar.

3. The combination as described in claim 2, said supporting frame (b)being formed with passages for the circulation of a cooling mediumtherethrough, and being provided with inlet and outlet pipes leading toand from said passages, said pipes being interchangeably connected 35 tofixed water supply and water drain pipes to permit the door to bereversed.

- References Cited in the file of this patent UNITED STATES PATENTSIndustrial Furnaces, vol. I (Trinks), published by John Wiley and Sons(New York), 1934 (page 308 relied on).

1. IN COMBINATION, (A) A REVERSIBLE OPEN HEARTH DOOR, COMPRISING (B) AMETALLIC SUPPORTING FRAME FACED ON BOTH SIDES WITH SIMILAR SEPARATE ANDDISTINCT INSERTS OF NONMETALLIC REFRACTORY MATERIAL, (C) MEANS FORSUPPORTING SAID DOOR FROM THE TOP OF SAID FRAME AND FOR RAISING ANDLOWERING SAID DOOR SUBSTANTIALLY IN A PLANE INTO OPEN AND CLOSEDPOSITION, COMPRISING (D) LIFTING MEANS ABOVE SAID FRAME, (E) A PIVOTALCONNECTION AT THE TOP OF SAID FRAME BETWEEN SAID FRAME AND SAID LIFTINGMEANS WITH A HORIZONTAL PIVOTAL AXIS EXTENDING ALONG THE LENGTH OF THEDOOR, AND (F) A SWIVEL CONNECTION AT THE TOP OF SAID FRAME BETWEEN SAIDFRAME AND SAID LIFTING MEANS AND LOCATED INTERMEDIATE OF THE SIDES OFTHE DOOR, SAID SWIVEL CONNECTION HAVING ITS AXIS EXTENDING CROSSWISE OFSAID DOOR, SUBSTANTIALLY IN THE PLANE OF SAID DOOR, (G) SAID PIVOTALCONNECTION AND SAID SWIVEL CONNECTION BEING CONNECTED IN SERIES BETWEENSAID LIFTING MEANS AND THE TOP OF SAID FRAME, AND (H) MEANS FOR SWINGINGSAID DOOR FORWARDLY AND UPWARDLY ABOUT SAID HORIZONTAL AXIS FROM SAIDFIRST MENTIONED PLANE TO A RAISED SUBSTANTIALLY HORIZONTAL POSITION ANDTHEN BACK AGAIN AND FOR SUPPORTING SAID DOOR IN SAID SUBSTANTIALLYHORIZONTAL POSITION IN CONJUNCTION WITH SAID DOOR SUPPORTING MEANS, ANDCOMPRISING (I) A LIFTING MEMBER, AND (J) MEANS FOR FORMING A SWIVELCONNECTION BETWEEN SAID LIFTING MEMBER AND THE BOTTOM OF SAID FRAMEINTERMEDIATE THE SIDES THEREOF COAXIAL WITH THE TOP SWIVEL CONNECTION(K) SAID SWIVEL CONNECTIONS PERMITTING ROTATION OF SAID DOOR 180* ABOUTSAID CROSSWISE SWIVEL AXIS, WHEREBY SAID DOOR WHEN IN SAID RAISEDSUBSTANTIALLY HORIZONTAL POSITION CAN BE ROTATED ABOUT SAID CROSSWISESWIVEL AXIS THROUGH 180* WHILE SUPPORTED BY SAID DOOR SUPPORTING MEANS(C) AND SAID DOOR SWINGING AND SUPPORTING MEANS (H) WITH SAID CROSSWISESWIVEL SWIVEL AXIS SUBSTANTIALLY HORIZONTAL.